The present invention relates to medical infusion devices, and, more particularly, to variable flow rate regulators for accurately regulating the effluent flow from a source of pressurized fluid.
Intravenous or other parenteral administration of fluids is routinely performed in hospitals, other medical facilities, and emergency sites in the field. Depending upon the nature of the infusate, it is desirable for the clinician to be able to accurately and rapidly select an appropriate rate of delivery. For example, infusion of normal saline or lactated Ringer's solution to achieve normovolemia during surgery or following trauma is typically accomplished at a relatively high flow rate. On the other hand, administration of certain antiarrythmics such as Lidocaine or Procanamide following myocardial infarction may desirably be accomplished at any of a variety of relatively slow rates. In addition, administration of certain antineoplastic agents must be performed at a very slow and constant rate over a prolonged period to avoid localized necrosis at the infusion site. Even the IV administration of antibiotics is desirable in some circumstances, at relatively slow delivery rates such as 50 cc over 90 minutes or more. Not only do a large variety of situations exist which each require unique flow rates, but it may also be desirable in certain applications to be able to vary the flow rate once infusion has commenced.
A number of flow regulators have been developed from the simple adjustable clamp and counting of drips per minute to elaborate peristolic pump devices. Nonetheless, there remains a need for a variable flow regulator which is accurate, capable of providing any of a number of convenient preselected flow rates, and yet which is inexpensive to produce. In addition, there exists a need for such a device which is compact and simple to use, thereby accommodating the needs in the operating room, in the field, and of the ambulatory patient, while at the same time providing for precise delivery rates with minimal operator error and offering tamper-proof setting of the flow rate. Moreover, there exists a need to be able to quickly and accurately confirm the flow rate setting of the variable flow controller.